The objectives of the proposed research are to determine precisely the nutrient requirements of normal and malignant cells derived from similar tissues in the same species, and to catalog the differences that are found. Work is in progress and will be continued with several experimental systems, including normal and transformed WI-38 cells, "normal" and transformed 3T3 cells, and normal mouse embryo fibroblasts and transplantable tumors from mice. For each type of cell, the nutrient requirements will be defined as precisely as possible, both qualitatively and quantitatively, and apparent differences between cell types will be examined in detail. Preliminary studies seeking to obtain growth of additional types of cells will also be continued, with particular emphasis on obtaining growth of human epidermal keratinocytes without the use of a feeder layer, so that detailed nutritional analysis can be undertaken with those cells. Hopefully the differences in nutrient responses between normal and transformed cells that are beginning to be detected can ultimately be utilized to advantage in the design of cancer therapy programs. BIBLIOGRAPHIC REFERENCES: Shipley, G. and R.G. Ham 1976. Improved media for clonal growth of mouse 3T3 cells and mouse embryo fibroblasts. Agy, P. and R.G. Ham 1976. Improved medium for clonal growth of mouse neuroblastoma cells.